On 11/04/2024 7:04 a.m., Martin Maechler wrote:
Michael Chirico
on Mon, 8 Apr 2024 10:19:29 -0700 writes:
> Right now, attaching the same package with different include.only= has no
> effect:
> library(Matrix, include.only="fac2sparse")
> library(Matrix)
> ls("package:Matrix")
> # [1] "fac2sparse"
> ?library does not cover this case -- what is covered is the _loading_
> behavior of repeated calls:
>> [library and require] check and update the list of currently attached
> packages and do not reload a namespace which is already loaded
> But here we're looking at the _attach_ behavior of repeated calls.
> I am particularly interested in allowing the exports of a package to be
> built up gradually:
> library(Matrix, include.only="fac2sparse")
> library(Matrix, include.only="isDiagonal") # want: ls("package:Matrix")
-->
> c("fac2sparse", "isDiagonal")
> ...
> It seems quite hard to accomplish this at the moment. Is the behavior to
> ignore new inclusions intentional? Could there be an argument to get
> different behavior?
As you did not get an answer yet, ..., some remarks by an
R-corer who has tweaked library() behavior in the past :
- The `include.only = *` argument to library() has been a
*relatively* recent addition {given the 25+ years of R history}:
It was part of the extensive new features by Luke Tierney for
R 3.6.0 [r76248 | luke | 2019-03-18 17:29:35 +0100], with NEWS entry
• library() and require() now allow more control over handling
search path conflicts when packages are attached. The policy is
controlled by the new conflicts.policy option.
- I haven't seen these (then) new features been used much, unfortunately,
also not from R-core members, but I'd be happy to be told a different story.
For the above reasons, it could well be that the current
implementation {of these features} has not been exercised a lot
yet, and limitations as you found them haven't been noticed yet,
or at least not noticed on the public R mailing lists, nor
otherwise by R-core (?).
Your implicitly proposed new feature (or even *changed*
default behavior) seems to make sense to me -- but as alluded
to, above, I haven't been a conscious user of any
'library(.., include.only = *)' till now.
I don't think it makes sense. I would assume that
library(Matrix, include.only="isDiagonal")
implies that only `isDiagonal` ends up on the search path, i.e.
"include.only" means "include only", not "include in addition to
whatever else has already been attached".
I think a far better approach to solve Michael's problem is simply to use
fac2sparse <- Matrix::fac2sparse
isDiagonal <- Matrix::isDiagonal
instead of messing around with the user's search list, which may have
been intentionally set to include only one of those.
So I'd suggest changing the docs to say
"[library and require] check and update the list of currently attached
packages and do not reload a namespace which is already loaded. If a
package is already attached, no change will be made."
Duncan Murdoch
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
